The present invention is directed toward optical communication systems.
WDM systems are currently being deployed in order to increase the bandwidth or capacity of fiber optic networks. WDM systems typically include a plurality of transmitters, each respectively transmitting signals on a designated one of a plurality of channels or wavelengths. Each transmitter has an associated remodulator, which converts the wavelength of optical signals external to the WDM system to one of the WDM wavelengths. The channels are combined by a multiplexer at one end terminal and transmitted on a single fiber to a demultiplexer at another end terminal where the channels are separated and supplied to respective receivers. Typically, the receivers generate output optical signals corresponding to the optical signals input to the remodulators.
For monitoring purposes, it is advantageous to readily ascertain input and output optical signals associated with a given WDM channel. In WDM systems having low channel counts, e.g., less than 16, it is relatively easy to identify channel assignments. For systems having channel counts in excess of 100, however, it is difficult to trace a given output optical signal from the WDM system to the corresponding channel it was transmitted on because there are a large number of optical signals supplied to and output from the WDM system.